In a recently published paper in PeerJ journal entitled “Comparative genomics of non-pseudomonal bacterial species colonizing young cystic fibrosis patients,” researchers from Australia analyzed a series of non-pseudomonal strain isolates in order to determine the emergence of antibiotic resistance or unique virulence traits of the bacterial colonies in cystic fibrosis (CF).
Cystic fibrosis is a genetic disease that damages organs like the lungs, liver, kidneys, pancreas, and digestive system. CF causes the cells that produce mucus, sweat, and digestive juices to build up and become thick, inducing structural changes. Consequently, patients with CF may suffer from cough, repeated lung infections, inability to gain weight, fatty stools, infertility, and slow growth. The disease is a life-limiting condition, affecting about 70,000 people worldwide. Though the primary causes of the disease are related to genetic mutations, patients with CF are particularly predisposed to infections of lungs with bacteria called Pseudomonas aeruginosa (P. aeruginosa). The infection is caused by the characteristic mucus build-up in CF that creates a suitable environment for the bacteria to thrive. As a consequence, about 40% of CF patients between 6 to 10 years old are reportedly infected with P. aeruginosa.
There is no cure for cystic fibrosis, but the disease can be managed by various treatments to ease symptoms and reduce complications, including antibiotics. It is has been reported that early treatment of P. aeruginosa infections with antibiotics improve patient outcomes. Nevertheless, there is a concern regarding the possibility that other similar bacterial species would colonize the CF vacate airways. Furthermore, long-term antibiotic therapy administrated to patients with CF may provide convenient environment for development of resistant bacterial strains.
To answer these questions, researchers from Australia performed an analysis of 28 non-Pseudomonas bacterial strains isolated from three young CF patients using a laboratory process that determines complete DNA sequence. The results illustrated that despite containing similar virulence genes, no particular resistance to antibiotics has emerged in these isolate colonies when compared to other examples of the same species. However, despite the treatment with antibiotics, it is found that several strains have persisted. For example, it is observed that same bacterial stain of Staphylococcus aureus has persisted for almost 1 a year. Furthermore, isolates of multi-drug resistant organisms Achromobacter xylosoxidans and Stenotrophomonas maltophilia showed that S. maltophilia strains raised no concern, but A. xylosoxidans persisted for almost five years.
In conclusion, these findings suggest that the analyzed collection of isolates showed no altered virulence behavior when compared to other isolates of same species. However, A. xylosoxidans is highlighted as a species of concern in CF patients because of its ability to persist for long periods. The latter may or may not be associated with antibiotic resistance.